/****************************************************************************
 *
 * Copyright 2016 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied. See the License for the specific
 * language governing permissions and limitations under the License.
 *
 ****************************************************************************/
/****************************************************************************
 * kernel/wqueue/kwork_signal.c
 *
 *   Copyright (C) 2014, 2016 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <signal.h>
#include <errno.h>

#include <tinyara/wqueue.h>

#include "wqueue/wqueue.h"

#ifdef CONFIG_SCHED_WORKQUEUE

/****************************************************************************
 * Public Functions
 ****************************************************************************/
/****************************************************************************
 * Name: work_signal
 *
 * Description:
 *   Signal the worker thread to process the work queue now.  This function
 *   is used internally by the work logic but could also be used by the
 *   user to force an immediate re-assessment of pending work.
 *
 * Input parameters:
 *   qid    - The work queue ID
 *
 * Returned Value:
 *   Zero on success, a negated errno on failure
 *
 ****************************************************************************/

int work_signal(int qid)
{
	pid_t pid;
	int ret;

	/* Get the process ID of the worker thread */

#ifdef CONFIG_SCHED_HPWORK
	if (qid == HPWORK) {
		pid = g_hpwork.worker[0].pid;
	} else
#endif
#ifdef CONFIG_SCHED_LPWORK
		if (qid == LPWORK) {
			int wndx;
			int i;

			/* Find an IDLE worker thread */

			for (wndx = 0, i = 0; i < CONFIG_SCHED_LPNTHREADS; i++) {
				/* Is this worker thread busy? */

				if (!g_lpwork.worker[i].busy) {
					/* No.. select this thread */

					wndx = i;
					break;
				}
			}

			/* Use the process ID of the IDLE worker thread (or the ID of worker
			 * thread 0 if all of the worker threads are busy).
			 */

			pid = g_lpwork.worker[wndx].pid;
		} else
#endif
		{
			return -EINVAL;
		}

	/* Signal the worker thread */

	ret = kill(pid, SIGWORK);
	if (ret < 0) {
		int errcode = errno;
		return -errcode;
	}

	return OK;
}

#endif							/* CONFIG_SCHED_WORKQUEUE */
